It doesn’t take much to tear a hole in an eardrum. Infections and injuries are common causes, but perforations can even be caused by the change in pressure scuba diving.
Fixing them isn’t always straightforward, as Nicole Black, 30, learned when she met two ear doctors while in graduate school for engineering sciences at Harvard. Eardrum repair procedures typically involve cutting a bit of tissue or cartilage from another part of the head and using it to patch up the hole. They aren’t always successful, and patients often require follow-up operations years later.
So she set out to develop a better treatment. Her goal was to 3D-print an all-new material that could be used in a patch—one that works like a healthy eardrum.
It wasn’t easy, because the eardrum has special properties that allow it to conduct sound waves. “Your eardrum vibrates like a soft material at low frequencies and like a stiff material at high frequencies,” says Black. The material needed to be able to support the growth of cells, including blood vessels. And it needed to be strong enough to withstand being handled by surgeons. But the human eardrum is only around 80 microns thick—around the width of a human hair. “It was a lot of trial and error,” she says.
Black began testing the devices on perforated eardrums in chinchillas—chosen for their huge ears. These animals have eardrums that are almost the same size as human ones. When she started getting promising results, she cofounded a company, Beacon Bio, to develop them further. That company was soon acquired by the 3D-printing firm Desktop Metal, where Black is currently vice president of biomaterials and innovation at the healthcare division, Desktop Health.
Black says her most significant breakthrough was being able to print a material with a structure that encourages cells to grow in specific patterns. This is essential for the eardrum, but it will also prove useful in 3D-printing medical devices for other organs and tissues, she says.
The latest version of her device, called the PhonoGraft, is shaped a bit like a flattened spool of thread, so it can be squeezed through a hole in an eardrum until half pops through to the other side.
The simplicity of its design means that you wouldn’t need an otologist to insert it—theoretically “any trained ear, nose and throat (ENT) specialist who can look in your ear with an endoscope can place one of these,” says Black, who hopes to start testing the device in humans toward the end of 2024.
Black also plans to create devices for other health needs. Her next goal is to create vascular grafts, which help repair damage to blood vessels—for example, after bypass surgery.
